Direct-current signaling system.



v mmmm B. F. GARDNER.

DIRECT CURRENT SIGNALING SYSTEM. APPLICATION FI'LED N0v.24, 1917.

Patented Apr. 22,191R.

BENJAMIN EULTON GARDNER, OF CHICAGO, ILLINOIS, ASSIGNOR, OF ONE-HALF T0 SEYMOUR STEDMAN, 01E CHICAGO, ILLINOIS.

DIRECT-CURRENT SIGNALING SYSTEM.

Specification of Letters Patent.

Patented Apr. 22, 191%).

Application filed November 24,, 1917. Serial No. 203,680.

To all whom it may concern:

Be it known that L-BENJAMIN FULTON GARDNER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Direct-Current Signaling Systems, of which the following is a specification.

My invention relates to improvements in direct current signaling systems and my object is to provide means by which a relatively high voltage direct current service line may be made to energize a relatively low voltage signaling circuit.

The invention will be fully understood from the following specification taken in connection with the accompanying drawing which represents diagrammatically a signaling system designed in accordance with the invention.

Referring to this drawing, the numeral 1 designates a relatively high voltage direct current circuit as, for example, a 110 volt city service line. Inseries with this line there is a relay contact device 2, the primary winding 3 of an induction coil, and a vibrator contact device 4 operable by the said coil. The contacts of the vibrator are bridged in the usual manner by a condenser 5.

lhe signalingcircuit per se is designated 6 and includes the signaling apparatus, such as, for example, the hell 7, the control switch shown as a push-button 8, a battery cell 9, and the winding 10 of the relay magnet which operates the relay contact 2.

The system; is completed by a third circuit 11 which is in series with the secondary winding 12 of the induction coil and is connected to the signaling circuit 6 to bridge the signaling device 7 thereof.

The operation of my improved signaling system is as follows:

By the actuation of the push-button 8 the signaling circuit 6 becomes energized with the voltage of the single battery cell 9. This ener 'zation will in general be insufiicient to a cot the signaling device per 86. It will, however, be sufiicient to operate the relay 10 which may be made exceedingly sensitive. Through the operation of this relay the 110 volt circuit 1 will be closed at the relay contact, thus energizing the primary winding of the induction coil 3 and causing the vibrator 4 thereof to operate to open and close this circuit rapidly. The secondary winding 12 of the induction coil will thereby be ener gized and through it the. circuitll which is bridged around the signaling device 7. As is shown diagrammatically upon the drawing, the number of turns in the secondary winding 12' is much less than the number of turns in the primary winding 3, so that the induction coil operates as a step-down transformer, the proportionate number of turns in the winding being calculated to give the desired voltage for the actuation of the signaling device. It will be apparent, therefore, that by the actuation of the push-button or other controlling switch 8 in the sig naling circuit the high voltage circuit is automatically closed to energize the induction coil therein, and that from the secondary winding of this coil the supply of electrical energy at a low potential required for the actuation of the signaling apparatus is obtained.

When the signaling circuit is opened, as by the release of the push-button 8, the winding of the relay 10 becomes decnergized, thereby permitting the high voltage circuit to open at the relay contact 2.

It should be noted particularly that the secondary circuit 11 is connected with the signaling circuit 6, the bell 7 forming a common bridge between the two circuits. The signaling device or hell 7 being of the circuit interrupting type, it follows as a result of this form of connection that the secondary circuit flows through the relay circuit when the current has been interrupted in the operation of the signaling device 7. Consequently the circuit 11 acts to lock the relay during the period when the circuit 6 is interrupted. An energizing circuit is thu maintained through the relay during the, en- *tire time that the push button 8 is held down. The release of the push-button 8 will then not only open the battery circuit through the relay winding 10, but also open t the bridge circuit 11 through the relay winding 10. The relay winding 10 will also be of relatively high resistance as compared with the signaling device, such as the hell 7 in order that under operation the shunt path around the signaling device (with re spect to the circuit 11) shall not draw any appreciable current.

' In practice the induction coil and condenser Wlll preferably be mounted within or upon a'single properly insulated struc turalunit conveniently located with respect to the service lines 1. The signaling wiring proper will therefore include'only the low voltage circuits 6 and 11, the latter being only of suflicient length to permit proper connections with the circuit 6.

By my invention it will be seen that means is provided for energizing the low voltage signaling circuit from a relatively high voltage direct current line, this energization being efi'ected without providing any connections whatever between the high voltage and the low voltage circuits (save the magnetic connection through the coil). It will therefore be permissible to make use of the ordi nary low voltage signaling circuit construc-' tion and without providing any additional insulation or other safeguard which would be re uired were there any electrical connections etween the high voltage and the low voltage line.

While I have described in considerable detail one specific embodiment of my invention, it will be understood that this is illustrative only and for the purpose of making the invention more clear, and that I do not and a relay winding, a contact device operisomers able by the relay and adapted t open and close the service line, and connections between the secondary winding of said induc-' tion coil and the said signaling circuit for energizing the latter from the former.

2. In a system of the class described, a relatively high voltage service line, an induction coil and a magnetic circuit interrupter therein, a signaling circuit including a control device, a source of potential and a relay winding, a contact device operable by the relay and in series with the service line, and connections between the secondary winding of the said induction coil and the said signaling circuit, said control device lying between one of said connections and the relay winding.

3. In a slgnaling system of the class described, a relatively high voltage service line, an induction coil and a magnetic circuit interrupter therein, a signaling circuit including signaling devices, a control switch, a source of potential and a relay winding, a relay contact device in series with the said service line, and connections between the secondary Winding of the said induction coil .and the said signaling circuit, said connections shunting the signaling device therein with respect to the relay winding and control switch.

4. in a system of the class described, a relatively high voltage service line, a signaling circuit, means included in said circuit adapted to close the service line when energized, a signal energizing circuit comprising means for deriving an induced current from said service line, and a circuit interrupting signaling device forming a common bridge across the signal circuit and the signal energizing circuit.

BENJAMIN FULTON GARDNER. 

